Comparing treatment outcomes of stage IIIB cervical cancer patients between those with and without lower third of vaginal invasion

OBJECTIVE: To evaluate treatment outcomes between stage IIIB cervical cancer with and without lower third of vaginal invasion (LTI) in terms of response to treatment and overall survival (OS). METHODS: Matching one patient with LTI for 2 patients without LTI who had completed treatment between 1995 and 2012 were conducted by using treatment modalities (radiation therapy [RT] alone vs. concurrent chemoradiation therapy [CCRT]) and tumor histology (squamous cell carcinoma [SCC] vs. adenocarcinoma [ADC]). Treatment outcomes including complete response (CR) rate of RT/CCRT, patterns of treatment failure and survival outcomes were analyzed. RESULTS: Of 216 stage IIIB cervical cancer patients, 114 of them had no LTI and 72 had LTI. Most of the patients (83.8%) had tumor histology as SCC. The CR rates between stage IIIB without LTI and with LTI were 93.8% and 81.9% (p=0.009), and corresponding with disease progression at pelvis accounted for 18.2% and 34.4% (p=0.017), respectively. Distant metastasis was comparable between 2 groups of patients, 28.9% in patients without LTI and 29.5% in patients with LTI (p=0.988). The 2-year and 5-year OS of stage IIIB without LTI were 66.5% and 46.8% compared to stage IIIB with LTI which were 43.1% and 28.9% (p=0.004), respectively. For multivariable analysis, stage IIIB with LTI was only the influential factor on OS with hazard ratio (HR) of 1.63 (p=0.012). CONCLUSION: Stage IIIB cervical cancer patients with LTI have poorer treatment outcomes including response to treatment and survival outcomes than patients in the same stage without LTI.